1. Technical Field
The present invention relates generally to a method and apparatus for blocking fluid and fluid vapors. More particularly, the present invention relates to a unique method and construction of an apparatus for preventing fluid leakage and vapor migration through the use of connecting devices.
2. Discussion
Conventional automotive fuel delivery systems utilize an electric fuel pump mounted in a fuel tank to deliver fuel from the fuel tank to the engine. Power is supplied to the fuel pump through electric wires connected between the fuel pump and a voltage source such as an alternator or a vehicle battery. In order to reach the fuel pump, the electrical wires must pass through an opening in the fuel tank. Such an opening, unless properly sealed, potentially provides a pathway for fluid leakage and fluid vapor migration commonly referred to as vapor permeation. Minimizing such fluid leakage and vapor permeation is desirable due to increasing regulations regarding automotive fuel vapor emissions and overall product efficiency.
Several attempts to seal this opening in the fuel tank have been developed. Many of these contributions to the art include a fitting adapted for placement in the opening. The electrical wires then continuously pass through this fitting. Although the wires are fitted together as tightly as possible through the fitting, spaces or pores inevitably exist through which fluid leakage and vapor permeation is released.
In other contributions to the art, fluid leakage and vapor permeation is attempted to be prevented through the use of numerous continuous wires, the center portions of which are stripped of insulation. A plug is then placed over the exposed center insulation stripped wire portion. The entire composite is then blocked through a chemical bath treatment. Such contributions typically include production processes which are laborious and expensive, further possibly requiring separate internal and external harnesses. Moreover, the use of insulated continuous wire is rather costly and wasteful since this high end type of wire is only required in the area inside the fuel tank and not throughout the entire vehicle. Wires in the fuel tank are typically specially cured such as through chemical baths or through exposure to radiation to strengthen their various necessary attributes. This greatly increases the cost of the wires.
As set forth above, in order to maintain the electrical integrity of the connection, the electrical wires are typically wrapped with expensive insulation. Some such wire insulation swells when exposed to fluid or vapor permeation which may cause cracking and/or breakage. Other types of insulation shrink when exposed to fluid or vapor permeation, thus increasing the size of the pathway through which fluid leakage or vapor permeation may escape. When the insulation on the wires passing through a fitting deteriorates due to shrinking or swelling, or when the wires are not sufficiently bound to the fitting, the area between the wire and the fitting are widened providing a greater pathway through which fluid leakage or vapor permeation may be released.
In other processes, the center of the conductors is stripped and through a vacuum process, a fuel resistant sealant is introduced to fill the pores between the wires and the fitting. Such a contribution is illustrated in U.S. Pat. No. 5,631,445 (Herster). A welded or bonded section of wire has also been developed to prevent fluid leakage and vapor permeation. New wire is also being developed which includes a blocking agent added during the extrusion process.
The current contributions to the art do not effectively and consistently compensate for the problems set forth above, in part by failing to adequately seal and close the space between the wires and the fitting, by failing to sufficiently bond the wires to the fitting, and by failing to adequately and consistently seal the wires while maintaining the electrical integrity of the connection. In order to overcome the problems associated with the current contributions to the art, various designs and methods for blocking fluid and fluid vapors have been developed. The continued development has been directed to designs which simplify the manufacturing process and assembly while keeping costs at a minimum and performance at a maximum.
It is a principal object of the present invention to provide a method and apparatus for blocking fluid and fluid vapors which consistently eliminates the minute pathways from which fluid leakage and vapor permeation may escape. The term xe2x80x9cfluidxe2x80x9d will be used throughout, however, it will be appreciated that this term includes both fluid and fluid vapors.
A related object of the present invention is to provide a method and apparatus for blocking fluid and fluid vapors which allows for the use of a solid wire inside the fuel tank and a more cost effective wire outside the fuel tank.
It is another object of the present invention to provide a method and apparatus for blocking fluid and fluid vapors which includes connecting two separate wires together through the use of a connecting member, wherein a consistent, solid barrier is created while maintaining the electrical integrity of the connection. This entire connection is then overmolded with an appropriate fluid resistant material such as a plastic resin material from the acetyl family for fuel applications.
It is still yet another object of the present invention to provide a method and apparatus for blocking fluid and fluid vapors which is inexpensive to manufacture, compatible with automation and easy to install.
It is another object of the present invention to provide a method and apparatus for blocking fluid and fluid vapors which does not require the laborious and costly process of dipping the wires into a chemical bath and/or the use of the vacuum process.
It is another object of the present invention to provide a method and apparatus for blocking fluid and fluid vapors that utilizes a more costly, fluid resistant automotive grade wire inside the fuel tank and a more cost effective automotive grade wire outside the fuel tank.
In one form, the present invention provides a method for blocking fluid and fluid vapors including a connecting member. The method of the present invention includes the general steps of cutting an electrical wire and stripping the wire of its insulation at the cut ends. The wires are then attached onto the connecting member so as to maintain the electrical integrity of the connection. Finally, this connection, plus a portion of the wire insulation is overmolded with an appropriate fluid resistant material.
In another form, the present invention provides an apparatus for blocking fluid and fluid vapors including a connecting member and electrical wires which are cut and stripped of their insulation at the cut ends. The wires are then attached onto the connecting member so as to maintain the electrical integrity of the connection. The connection, plus a portion of the wire insulation, is then overmolded with an appropriate fluid resistant material.